Shimano RD-2400 medium cage rear mech. This is the replacement for the 2300 series rear mechs. It is an 8 speed mech and is compatible with all shimano 8 speed shifters.
The rear cage has a light weight resin inner plate and the stone finish on it adds a nice touch.
Rear max large sprocket size 32T
Rear min large sprocket size 25T
Rear max small sprocket size 13T
Rear min small sprocket size 11T
That is a 11-32T cassette with a chainset with 20T tooth count difference. So it will work with MTB drive trains too.
The short cage mech is designed to work with the double chainset. If you are running a triple chainset you will need the medium cage version.